The BNORC Transgenic Core (Bradford Lowell, Director) is a fee-for-service facility that takes investigator- derived DNA constructs or investigator derived (or obtained) genetically modified embryonic stem (ES) cells to create founder transgenic and gene knockout or gene knockin mice (i.e. mice bearing point mutations, lox- modified or ires/2A-Cre knockin alleles) that can be used to address questions relevant to diabetes, obesity, and nutrition, including questions related to brain control of feeding, metabolism, and hunger / reward. The Transgenic Core is heavily utilized. In the last 4 year cycle (2012-2016), the Core performed 188 projects (27 projects involving transgenic DNA injection and the injection of CRISPR/Cas9 reagents, 59 projects involving generation of targeted ES cell clones, 83 projects involving blastocyst injection of targeted ES cell clones, and 19 projects involving cryopreservation and in vitro fertilization). This number of projects performed during this shortened 4 year cycle represents a continued marked increase in the number of projects over prior 5 year cycles ending in 1997 (54 projects), 2002 (91 projects), 2007 (120 projects) and 2012 (162 projects). This demonstrates progressively increasing, substantial demand for BNORC Transgenic Core services. Importantly, mice generated by the Core have had a major impact on science. In the last 4 year cycle (2012- 2016), BNORC Transgenic Core-generated mice have been featured in 389 publications (124 authored by BNORC Core members and 265 authored by Non-BNORC members ? the latter demonstrating extensive sharing of BNORC Transgenic Core-generated mice with other labs). 53 of these publications were in Cell, Nature and Science, and 55 were in Cell Metabolism, Nature Neuroscience and Neuron. With regards to development of new technology, the BNORC Transgenic Core has implemented CRISPR/Cas9-related approaches to engineer the mouse genome. This will further expand usage by BNORC members.